Vanillin is a major constituent of vanilla, used as a food flavoring, and is also a precursor to pharmaceutical manufacture. The utilization of raw wood as a source of vanillin can be costly due to timber supply shortages and the potential impact on the environment. In abundant supply and at relatively low cost is old newsprint. Old newsprint is primarily made with high thermomechanical and chemthermomechanical pulp. Therefore, the lignin content is substantial and offers a potential raw material for the manufacture of vanillin.
It is an object of the present invention to provide a method for recovering lignin in quantities equal to or greater than current commercial processes. Further, it is an object to recover material of satisfactory quality for the manufacture of vanillin and other value added lignosulfonate products such as oil well drilling mud additives, textile dye dispersants, and admixtures to improve concrete strength. It is an objective that the lignosulfonate recovered have a high degree of sulfonation and low free-sugar content, the qualities of an excellent starting material for the manufacture of specialty chemicals based on lignosulfonates. The present invention relates to a method which meets these needs.
All percentages and ratios given are on a weight basis unless otherwise indicated.